plenum gasket question

i have a 94 jgcl 5.2 and it knocks when i accelerate. i read a write up on the plenum gasket and it sounds like what they described. my question is how much would a mechanic charge for a job like that if anyone hadit done. i saw the do it yourself write up and its ALOT of work. any info would be great thanx

what kind of knocking do you hear. I know the TSB you are referring to it has to do with DETONATION/PINGING, what kind of noise is it.

Does it sound like a rattling noise in you engine, like a ball bearing in the combustion chamber?

its sounds like it has very cheap gas when i accelerate from like 25 mph to go faster. not flooring the pedal but halfway.

it kinda does sound like something is bouncing around in there when i accelerate more than the usual

I have this same sound in my 94 5.2. I have tried the Wire rerouting (TSB), I replaced my Plenum and Intake manifold-head gaskets a lil over a year ago when I replaced my engine so I don't think thats the problem, I also performed the test using a vacuum guage and didn't get an accurate reading from it, so I was kinda lost. I also seen something about the dealerships using a dye in the oil and disconnecting the breather filters and PCV valves and plugging there ports in the intake and driving for a couple days then check inside the intake using a black light to see if there was any dye present.

There is actually a website based on the Magnum 318/360 engines and their imfamous pinging, It tells alot about the pinging and what causes it and how to get rid of it.

I have been able to get rid of mine by switching to 93 octance, but I cannot afford it...lol

Some of the stuff the site mentioned was Indexing the spark plugs, regapping them bigger (.045" - .060") , water injection, cooler plugs (1 heat range cooler), and a few more suggestions along with the 2 TSB's.

I have tried running cooler plugs, the TSB's, regapping to .045" and still have had no such luck getting rid of it.

here is the site: http://www.dodgeram.org/tech/gas/Trouble/ping.htm

Let me know if you find anything that works.

thanks for all the info. i bought this truck last year and it looks like it still has the original wires and plugs in it but who knows. it has 140k on it and i'm just gonna go with a major tune up and see how that works. it started to shutter a few months ago and gets noticeably worse when it is damp or raining out. hopefully a tune up will fix that problem also.

Seems this pinging is caused by some crankshaft issues. The magnum engine should be running a compression ratio around 9:1 but one or more of the cyl. could be closed to 9.5:1. I would do a compression test to determind if the crank is out of spec. on your engine. Also, I recomend finding a cooler thermostat to lower engine temp, this will lower the chances of your engine pinging. Otherwise you can go buy expensive high octane gas to get rid of the ping.

i am running the lowest therm i could get, i think it was a 170ish or less and i also put in a new 3 row radiator. hopefully a tune up will cure part of the problem if not all

well I guess the tune-up would be worth a try. I haa a 160 degree in my jeep up to about a week ago, replaced it because when it was about 45 degrees outside my temp engine temp was at about 130, which when it gets colder out the engine will be cooler and then I will have heating problems, so I will run the stock 195 until spring comes around. The 160 degree did not help with my pinging tho.